Biochemical treatment device with dispensing unit

ABSTRACT

The width of reaction wells and detection wells used for the same sample in a nozzle line direction is made to fall within an area smaller than the pitches of nozzle holding parts, so as to minimize a moving range and enable a pipette action for preventing contamination.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a biochemical reaction treatmentdevice, and more particular to a nucleic specimen treatment device fortesting existence of genes derived from disease germs in a sample suchas blood.

2. Description of the Related Art

Many methods are proposed which adopt a hybridization reaction using aprobe carrier represented by a DNA microarray as a method for quicklyand precisely analyzing a base sequence of nucleic acids and detectingtarget nucleic acids in a nucleic specimen. To obtain the DNAmicroarray, a probe having a base sequence complementary to the targetnucleic acids is fixed on a solid phase such as a bead and a glass platewith high density, and a method for detecting the target nucleic acidsusing the DNA microarray generally has following steps.

In a first step, the target nucleic acids are amplified by anamplification method represented by a PCR method. Concretely, first andsecond primers are first added to the nucleic specimen, and atemperature cycle is applied (hereinafter referred to as “1st PCR”). Thefirst primer is specifically bounded with some of the target nucleicacids, and the second primer is specifically bounded with some of thenucleic acids complementary to the target nucleic acids. Whendouble-stranded nucleic acids including the target nucleic acids arebounded with the first and second primers, the double-stranded nucleicacids including the target nucleic acids are amplified by an elongationreaction.

After the double-stranded nucleic acids including the target nucleicacids are amplified sufficiently, substances other than amplifieddouble-stranded nucleic acids such as non-reacted primers and fragmentsof nucleic acids are removed by purification. Methods for adsorbing thedouble-stranded nucleic acids to magnetic particles or methods using acolumn filter are known as a purification method.

After completion of purification, a third primer is added to the nucleicspecimen, and the temperature cycle is applied (hereinafter referred toas “2nd PCR”). The third primer is marked with an enzyme, a fluorescentmaterial, a luminescent material or the like, and is specificallybounded with some of the nucleic acids complementary to the targetnucleic acids. When the third primer is bounded with the nucleic acidscomplementary to the target nucleic acids, the target nucleic acidsmarked with the enzyme, the fluorescent material, the light-emittingmaterial or the like are amplified by the elongation reaction. As aresult, when the nucleic specimen includes the target nucleic acids, themarked target nucleic acids are generated, and when the nucleic specimendoes not include the target nucleic acids, the marked target nucleicacids are not generated.

In a second step, the nucleic specimen is brought into contact with theDNA microarray, and is hybridized with the probe of the DNA microarray.Concretely, the temperatures of the DNA microarray and the nucleicspecimen are increased. If there is any target nucleic acidcomplementary to the probe, the probe and the target nucleic acids forma hybrid material.

In a third step, the target nucleic acids are detected. For example,when the maker materials are fluorescent materials, the fluorescentmaterials are excited by a laser and the like to measure a luminancethereof. That is to say, whether the probe and the target nucleic acidsform the hybrid material or not can be detected by marker materials ofthe target nucleic acids, thereby confirming a specific base sequence.

Such a DNA microarray utilizing this hybridization reaction is expectedfor application to a medical diagnosis for specifying the disease germsand a gene diagnosis for testing constitutions of patients. A diagnosismethod using such a DNA microarray utilizes a few kinds of liquids whileexchanging disposable pipette chips at a pipette tip. Therefore, thisoperation is very complicated, and a treatment capability is limited ina manual operation. To solve these problems, some devices are proposedwhich automate an amplification step, a hybridization step, a detectionstep and a dispensing step for moving and mixing the liquid.

Now, one example of a DNA testing device is shown in FIG. 5. In FIG. 5,a constitution using one pipette is shown. A DNA testing device 101comprises a dispensing unit 102, a base 108, a pipette chip case 110, anamplification plate 120 and a hybridization plate 130. The dispensingunit 102 can freely move in a space in the device by Z-direction movingmeans 104, X-direction moving means 105, and Y-direction moving means106 and 107. Here, the Z-direction is defined as a directionperpendicular to an XY-plane in FIG. 5. Also, the dispensing unit 102has a nozzle holding part 103, and the nozzle holding part 103 is fittedwith a pipette chip 111. The pipette chip is mounted by moving thenozzle holding part 103 to the pipette chip 111 of the pipette chip case110. The dispensing unit 102 to which the pipette chip 111 is mountedcan move the liquid contained in a well 121 of an amplification plate120 or a well 131 of a hybridization plate 130 by a pipette mechanism(not shown) to another well. The liquid is moved and mixed, andtemperature control means (not shown) controls the temperature of theliquid, so that a biochemical reaction can be promoted.

The constitution using only one pipette as shown in FIG. 5 requiresconsiderable times to treat a plurality of samples even in the case ofan automated device. Therefore, as described in Japanese PatentApplication Laid-Open Nos. H09-96643 and 2003-274925, devices forsimultaneously treating a plurality of samples with a plurality ofpipettes have been proposed.

In the constitutions described in Japanese Patent Application Laid-OpenNos. H09-96643 and 2003-274925, an action that the pipette treating acertain sample passes on the well holding a reagent for another samplemay be inevitable. During movement of the reagent, the liquid held inthe pipette chip might drop as micro-droplets due to vibrations and thelike of a carrying shaft. When the liquid including the other sample ismixed with the reagent, it becomes a cause of misjudgment at the time ofdiagnosis.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a biochemical treatmentdevice capable of effectively preventing contamination in light of theabove-mentioned problems.

A biochemical treatment device of the present invention comprises a basestand capable of mounting a reaction unit with a plurality of lines ofreaction area arranged at predetermined pitches so as to simultaneouslytreat a plurality of samples, wherein a plurality of lines of thereaction area are allocated to the same sample; a plurality of nozzlesarranged at predetermined pitches in a direction perpendicular to saidlines of reaction area; a dispensing unit holding the nozzles, whereinthe width of said lines of reaction area is narrower than the pitch ofthe nozzles; and a moving mechanism relatively moving the base stand andthe dispensing unit.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view for explaining the structure of anautomatic DNA testing device in an embodiment of the present invention.

FIG. 2 is a first plane view for explaining the action of an automaticDNA testing device in an embodiment of the present invention.

FIG. 3 is a second plane view for explaining the action of an automaticDNA testing device in an embodiment of the present invention.

FIGS. 4A and 4B show plane views and cross section views for explainingcassettes in embodiment of the present invention.

FIG. 5 is a plane view for explaining the structure of an automatic DNAtesting device of a prior art.

DESCRIPTION OF THE EMBODIMENTS

Now, embodiments of the present invention will be described withreference to the drawings.

Following is an embodiment, in which the present invention is appliedwhen existence and volume of target nucleic acids (DNA) in a nucleicspecimen are determined using a unit for a PCR as a reaction unit, a DNAmicroarray as a testing unit, and a pipette chip as a nozzle.

FIG. 1 is a perspective view for explaining the structure of anautomatic DNA testing device in an embodiment of the present invention.FIGS. 2 and 3 are plane views for explaining the action of an automaticDNA testing device in an embodiment of the present invention.

First, the structure of the automatic DNA testing device will beexplained with reference to FIG. 1. An automatic DNA testing device 1has a constitution that a dispensing unit 2, an amplification unit 3 anda hybridization unit 4 are arranged on a base 5. Also, a sample stage 7in which a sample solution to be tested is placed is provided on anupstream side of the amplification unit 3.

The dispensing unit 2 is supported by a mechanism capable of themovement of the dispensing unit in an X-direction (hereinafter referredto as “an X-shaft 6”), and an arm capable of the movement of thedispensing unit in a Z-direction (hereinafter referred to as “a Z-shaft21”). In this manner, the dispensing unit 2 can move in a space on theamplification unit 3 and the hybridization unit 4 in an XZ-direction.The illustrated device comprises nozzle moving means having thedispensing unit 2, the X-shaft 6 of the dispensing unit, and the Z-shaft21 of the dispensing unit. Also, the amplification unit 3 constitutes areaction unit, and the hybridization unit 4 constitutes a testing unit.A mechanism utilized in various treatment machines and reaction devicescan be used for each moving means of this device. For example, amechanism using a guide for restraining a moving direction, a belt orroller capable of moving an arm, stand or the like along the guide, anddrive means thereof can be utilized.

In the dispensing unit 2, pipette mechanisms 24 are fixed to a housing22, and nozzle holding parts 25 capable of mounting the pipette chipsare provided at the tips of the pipette mechanisms 24. The nozzleholding parts 25 are aligned at equal pitches in the Y-direction. Whenthe pipette mechanisms 24 are driven, liquid can be introduced in thepipette chips mounted to the nozzle holding parts 25, or the liquid canbe discharged from the pipette chips. A boring Z-shaft 23 is mounted tothe housing 22 of the dispensing unit 2, and boring mechanisms 26 arealigned at the tip of the boring Z-shaft 23 at pitches same as those ofthe nozzle holding parts 25 in the Y-direction. Thereby, regardless ofdrive of the dispensing unit 2 in the Z-direction, the boring mechanisms26 can be independently driven in the Z-direction. That is to say, theboring mechanisms 26 can be arranged above or below the nozzle holdingparts 25. The number of the boring mechanisms 26 is equal to that of thenozzle holding parts 25, and the positions in the Y-direction are equalto each other. Therefore, holes can be bored at positions for dispensingthe liquid with the nozzle holding parts 25.

The amplification unit 3 has a constitution that an amplification stage32 as an installation stand is mounted on the Y-shaft 31 of theamplification unit as relative moving means. The amplification stage 32can move in the Y-direction by the Y-shaft 31 of the amplification unit.An amplification plate 33 and a pipette chip case 35 can be arranged onthe amplification stage 32. The amplification plate 33 is a commerciallyavailable 96-well plate made of polypropylene with 8×12 amplificationwells 34. The amplification wells 34 are filled with a reagent and acleansing liquid used in a first PCR step (1st PCR), a purification stepand a second PCR step (2nd PCR) in advance. In a stage, in which theamplification plate is mounted in the device, a protective sheet (notshown) for preventing mixture of contaminants into each of theamplification wells 34 is adhered on the top face of the amplificationplate to cover opening faces of the respective amplification wells 34.Twelve pipette chips 36 are accommodated in one line in the Y-directionin the pipette chip case 35. Here, a line of the 12 amplification wells34 is matched with a line of the 12 pipette chips 36 in the Y-direction.Also, the pipette chip case 35 may be installed to at least one of thestages 32 and 42, the amplification unit 3 and the hybridization unit 4.

The hybridization unit 4 has a constitution that the hybridization stage42 as an installation stand is mounted to the Y-shaft 41 of thehybridization unit as relative moving means. The hybridization stage 42can move in the Y-direction by the Y-shaft 41 of the hybridization unit.A hybridization plate 43 and cassettes 50 can be arranged on thehybridization stage 42. The hybridization plate 43 is cut out of acommercially available 96-well plate made of polypropylene with 3×12hybridization wells 44.

Then, the action of the automatic DNA testing device according to thepresent invention will be explained with reference to FIGS. 2 and 3. Theaction for mounting the pipette chips will be first described. Thisaction starts from a condition that the pipette chips are not mounted tothe nozzle holding parts 25. As shown in FIG. 2, the amplification stage32 is moved to locate the pipette chips 36 on lines 61 to 66. Thereby,Y-coordinates of the nozzle holding parts 25 and the pipette chips 36are matched with each other. Then, the X-shaft 6 of the dispensing unitis moved so that the X-direction positions of the nozzle holding parts25 and the pipette chips 36 are matched with each other, and thedispensing unit 2 is lowered by the Z-shaft 21 of the dispensing unit.Thereby, the nozzle holding parts 25 are fitted with the pipette chips36. The 6 nozzle holding parts 25 with the identical shape are alignedin the Y-direction at equal pitches, and the 12 pipette chips 36 arealigned in the Y-direction at half pitches of the nozzle holding parts25. By this action, the pipette chips 36 are mounted to all of the 6nozzle holding parts 25. Here, the number of the nozzle holding parts 25is, but not limited to, designated as 6, and a desired number more thanone of the nozzle holding parts may be aligned in the Y-direction.Furthermore, although the nozzle holding parts 25, but not must be, arealigned at equal pitches, the pipette chips 36 accommodated in thepipette chip case 35 may be arranged at positions corresponding to thenozzle holding parts 25. When this constitution is explained withreference to FIG. 2, the dispensing unit 2 having 3 nozzle holding parts25 arranged only on the lines 61, 62 and 65 may do.

The boring mechanisms 26 are arranged above the nozzle holding parts 25by the boring Z-shaft 23. Thereby, at the time of mounting the pipettechips, the boring mechanisms 26 do not collide with the amplificationstage 32 and the like to block the action. Finally, the dispensing unit2 is raised by the Z-shaft 21 of the dispensing unit, so that thepipette chips 36 fitted with the nozzle holding parts 25 are detachedfrom the pipette chip case 35.

The action for removing the pipette chips will be explained. Forexample, when the pipette chips 36 on the lines 61 to 66 shown in FIG. 2are used, accommodation parts of the pipette chip case 35 on the lines61 to 66 shown in FIG. 2 are vacant. The used pipette chips are broughtback to the vacant accommodation part of the pipette chip case 35. TheX-shaft 6 of the dispensing unit and the Z-shaft 21 of the dispensingunit are driven, so that the pipette chips mounted to the nozzle holdingparts 25 are inserted in a vacant portion of the accommodation part ofthe pipette chip case 35. The pipette chips are detached from the nozzleholding parts 25 by a pipette chip ejecting mechanism (not shown)provided to the dispensing unit 2. Concretely, by pushing only thepipette chips downward, the nozzle holding parts 25 are disengaged fromthe pipette chips. Finally, the dispensing unit 2 is raised by theZ-shaft 21 of the dispensing unit, so as to finish the pipette chipremoving action.

The boring action will be now explained. A protective sheet (not shown)is adhered on the top faces of the amplification plate 33 and thehybridization plate 43 to prevent mixture of contaminants. Therefore,when the reagent and the cleansing liquid contained in the amplificationwells 34 and the hybridization wells 44 are used, it is required to borethe protective sheet. One example, when the 6 amplification wells 34 arebored where the X-direction is on the line 60 and the Y-direction is onthe lines 61 to 66 in FIG. 2, will be explained. First, the boringmechanisms 26 are brought below the pipette chips mounted to the nozzleholding parts 25 by the boring z-shaft 23. Thereby, the pipette chipsmounted to the nozzle holding parts 25 do not touch the amplificationstage 32 and the like. As shown in FIG. 2, the amplification stage 32 ismoved by the Y-shaft 31 of the amplification unit, so that theamplification wells 34 to be bored are located on the lines 61 to 66.Thereafter, the X-shaft 6 of the dispensing unit is driven, so that theboring mechanisms 26 are matched with the line 60. Under this condition,when the Z-shaft 21 of the dispensing unit is lowered, the boringmechanisms 26 project through the protective sheet on the top face ofthe amplification plate 33, so as to bore the top faces of the 6amplification wells 34. Finally, the dispensing unit 2 is raised by theZ-shaft 21 of the dispensing unit and the boring mechanisms 26 are drawnfrom the amplification plate 33, so as to complete the boring action.

The dispensing action will be explained. One example, when the samplesolution contained in the sample wells 8 arranged on the sample stage 7is moved to the 6 amplification wells 34 where the X-direction is on theline 60 and the Y-direction is on the lines 61 to 66 in FIG. 2, will beexplained. First, the boring mechanisms 26 are brought above the nozzleholding parts 25 by the boring Z-shaft 23, so as to prevent the boringmechanisms 26 from colliding with the amplification stage 32 and thelike to block the action. As shown in FIG. 2, the amplification stage 32is moved by the Y-shaft 31 of the amplification unit, so that theamplification wells 34 for dispensing the solution are located on thelines 61 to 66. The X-shaft 6 of the dispensing unit and the Z-shaft 21of the dispensing unit are driven, so that the tips of the pipette chipsmounted to the nozzle holding parts 25 are brought into contact with thesample solution in the sample wells 8. The pipette mechanisms 24 areactuated, so as to introduce the sample solution in the pipette chips.Under a condition that the sample solution is held in the pipette chips,the Z-shaft 21 of the dispensing unit is driven to remove the pipettechips from the sample wells 8. The X-shaft 6 of the dispensing unit isdriven, so that the nozzle holding parts 25 are matched with the line60. The tips of the pipette chips mounted to the nozzle holding parts 25are inserted in the amplification wells 34 by the Z-shaft 21 of thedispensing unit. The pipette mechanisms 24 are actuated to discharge thesample solution in the pipette chips to the amplification wells 34, sothat the sample solution is mixed with the reagent contained in theamplification wells 34. Finally, the dispensing unit 2 is raised by theZ-shaft 21 of the dispensing unit and the pipette chips are drawn fromthe amplification plate 33, so as to complete the dispensing action.

Now, the reagent and the cleansing liquid held by the amplificationplate 33 and the hybridization plate 43 will be explained. The reagentand the cleansing liquid required for treating the same sample (firstsample) are contained in the amplification wells 34 and thehybridization wells 44 on the line 61 shown in FIG. 2 and on the line 71shown in FIG. 3. Some of these wells are used for mixture-treatment, PCRreaction treatment and purification of the reagent and the cleansingliquid. The reagent and the cleansing liquid are moved from the wellsstoring the reagent and the cleansing liquid to the treatment wells bythe dispensing unit 2. As is similar to the lines 61 and 71, the reagentand the cleansing liquid are also contained in the amplification wells34 and the hybridization wells 44 on the lines 62 to 66 shown in FIG. 2and on the lines 72 to 76 shown in FIG. 3. Each of the wells forming twoadjacent lines is arranged to treat the same samples (second to sixthsamples). Thereby, a plurality of samples (first to sixth samples) canbe identically processed concurrently. The reagent and the cleansingliquid used for the same sample are located in two lines, because thereare many kinds of reagents and cleansing liquids. The two lines of thereagent and the cleansing liquid can restrain the X-direction length ofthe device. In this case, although the number of lines is two, thenumber may be one, or three or more. When the second line is used, theamplification stage 32 or the hybridization stage 42 may be moved in theY-direction by pitches of the amplification wells 34 or thehybridization wells 44 from a condition shown in FIG. 2 to a conditionshown in FIG. 3.

While the above-mentioned pipette-chip-mounting, pipette-chip-removing,boring and dispensing actions are done, each of amplification,purification and hybridization steps is promoted. According to the orderof the steps, the actions of the device will be explained with referenceto FIGS. 1 to 3.

First, the sample wells 8 containing the sample solution are arranged onthe sample stage 7. The amplification plate 33, the pipette chip case35, the hybridization plate 43 and the cassettes 50 to be used are seton the DNA testing device 1. Here, when the DNA testing device 1 isstarted, a DNA testing step is started.

The pipette chips 36 are first mounted to the nozzle holding parts 25.Then, the top faces of the amplification wells 34 containing a 1st PCRreagent are bored, and the sample solution is moved to the amplificationwells 34 containing the 1st PCR reagent from the sample wells 8 by thedispensing unit 2. After the 1st PCR reagent is mixed with the samplesolution, a temperature cycle is applied to the amplification wells 34containing mixture solution by temperature control means (not shown),thereby promoting the 1st PCR.

After completion of the 1st PCR, the step goes to the purification stepfor removing contaminants other than nucleic acids. Magnetic particlesspecifically adsorbing the nucleic acids are put in the amplificationwells 34 for purification treatment. 1st PCR products are moved to theamplification wells 34 containing the magnetic particles, so as toadsorb the nucleic acids to the magnetic particles. The magneticparticles are fixed on the bottom faces of the amplification wells 34 bymagnetic force generation means (not shown), and the solution in thewells is removed by the dispensing unit 2. Furthermore, the magneticparticles are cleansed with a plurality of cleansing liquids severaltimes. The cleansing liquid is moved to the amplification wells 34containing the magnetic particles by the dispensing unit 2, and mixedwhile a magnetic force is not applied. The magnetic particles are fixedon the bottom faces of the amplification wells 34 by magnetic forcegeneration means (not shown), and the used cleansing liquid is removedby the dispensing unit 2.

After completion of cleansing the magnetic particles, the nucleic acidsare removed. Mixture of contaminants leads to bad influences onjudgment. If the pipette chips used until that time continue to be used,contaminants adhered to the pipette chips might be mixed. Therefore, inthe purification step, it is preferable to exchange pipette chips. Inexchanging the pipette chips, the pipette chips may be returned to avacant accommodation part of the pipette chip case 35, and the unusedpipette chips 36 may be mounted to the nozzle holding parts 25.

Eluate is moved to the amplification wells 34 containing the magneticparticles by new pipette chips. Adsorption of the nucleic acids to themagnetic particles is released by the eluate. The magnetic particles arefixed on the bottom faces of the amplification wells 34 by magneticforce generation means (not shown), and the solution containing thenucleic acids is moved by the dispensing unit 2, thereby completing thepurification step.

The solution after the purification step is mixed with a 2nd PCR reagentcontained in the amplification wells 34, and a temperature cycle isapplied by temperature regulation means (not shown), thereby promotingthe 2nd PCR. When the temperature cycle is finished, the amplificationstep is completed. By the 2nd PCR, when the target nucleic acids areamplified in the 1st PCR, fluorescent markers are given to them.

The liquid containing amplification products is moved to thehybridization wells 44 containing the hybridization reagent by thedispensing unit 2. After the amplification products are mixed with thehybridization reagent, mixture liquid thereof is moved to the cassettes50. FIG. 4A shows a plane view of the cassettes, and FIG. 4B shows across section view of the cassettes. The cassette 50 comprises a housing51 and a DNA microarray 52. Injection ports 53 are bored on the topfaces of the cassettes 50, from which the mixture liquid is dispensed toa liquid storage chamber 55 by the dispensing unit 2. Suction ports 54are provided on opposite sides of the injection ports 53, with whichsuction mechanisms (not shown) are brought into close contact to suckthe air. Then, the mixture liquid is introduced to a reaction chamber 57through a flow path 56. Thereby, the mixture liquid can be brought intocontact with the DNA microarray 52. Furthermore, the temperature of themixture liquid in the reaction chamber 57 is raised by temperatureregulation means (not shown), so as to promote the hybridizationreaction.

After completion of the hybridization reaction, the air is further drawnfrom the suction ports 54. Then, the mixture liquid moves through a flowpath 58 to a waste chamber 59. The surface of the DNA microarray 52 isthen cleansed. The hybridization wells 44 hold several kinds ofcleansing liquids. The cleansing liquids are carried to the liquidstorage chamber 55 of the cassette 50 by the dispensing unit 2 and theair is drawn from the suction ports 54, so that the cleansing liquidspass through the surface of the DNA microarray 52. The cleansing liquidsmove to the waste chamber 59, and do not leak to outside of thecassettes 50. By repeating this several times, the surface of the DNAmicroarray 52 is completely cleansed.

After completion of the hybridization reaction, a detection system 40arranged below the hybridization stage 42 judges existence and volume ofthe reaction between the target nucleic acids and probe nucleic acidsfixed to the DNA microarray. As in the above-mentioned example, whenfluorescent marker is given to the target nucleic acids, lights excitingthe fluorescent markers are radiated to the DNA microarray, so as tomeasure fluorescence or fluorescent volume at each of probe fixingspots. If the detection system 40 detects the fluorescence orfluorescent volume, the cassettes 50 have optical paths capable ofradiating excitation lights and measuring fluorescence. Existence orvolume of target substances in the sample is obtained on the basis ofdata relating to the resultant fluorescence. Herein, although thedetection system 40 is arranged below the hybridization stage 42, thedetection system 40 may be arranged in a testing space separatelyinstalled in the device and the cassettes 50 may be conveyed to thetesting space by a conveying arm. Furthermore, the detection system maybe arranged to the other detecting device and the cassettes 50 after thehybridization reaction may be removed and set to the detecting device.

All or desired parts of each of the above-explained actions can beautomatically performed by a program preinstalled to a computer mountedto the device or having a structure mountable to the device.

As described above, if the width of the amplification well lines and thehybridization well lines used for the same sample is made narrower thannozzle pitches, when pipette chip treating this sample moves along thesewell lines, the pipette chip does not pass above the other well linesholding the reagent for the other sample. Or, the pipette chip adjacentto this pipette chip for treating the other sample does not pass on thetarget well lines of the first-described pipette chip. Herein, oneexample, when the nozzle pitches are equal to each other, is described,but even when the nozzle pitches are not equal, the width of theamplification well lines and the hybridization well lines used for thesame sample is made to fall within an area smaller than the narrowestwidth of the nozzle pitches, so that a similar effect can be obtained.

Such a pipette action can prevent contamination due to drop of droplets.Also, under a condition that the pipette chip case is placed on the welllines and the pipette chips are prepared for the case, the width of thepipette chips used for the same sample in a nozzle arranging directionis made to fall within an area narrower than the nozzle pitches, so thata risk of contamination to unused chips can be effectively eliminated.When many kinds of reagents are required, the size of the device can berestrained by locating reaction wells in a plurality of lines.Furthermore, because the reaction wells used for the same sample arearranged all together, the moving distance of the pipette chips can berestrained small, and the tact of the dispensing step can be shortened.Also, because a plurality of reaction units are provided withindependent reaction unit moving means, a plurality of reactions can bemade concurrently, so as to improve treatment capacity of the automaticDNA testing device.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims priority from Japanese Patent Application No.2005-291770 filed on Oct. 4, 2005, which is hereby incorporated byreference herein.

1. A biochemical treatment device comprising a base stand capable of mounting a reaction unit with a plurality of lines of reaction area arranged at predetermined pitches so as to simultaneously treat a plurality of samples, wherein a plurality of lines of the reaction area are allocated to the same sample; a plurality of nozzles arranged at predetermined pitches in a direction perpendicular to said lines of reaction area; a dispensing unit holding said nozzles, wherein the width of said lines of reaction area used for the same sample is narrower than the pitch of said nozzles; and a moving mechanism relatively moving said base stand and said dispensing unit.
 2. The biochemical treatment device according to claim 1 wherein said moving mechanism moves said base stand in the same direction as an aligning direction of said nozzles.
 3. The biochemical treatment device according to claim 1 wherein said reaction unit has an amplification reaction unit, a hybridization reaction unit and a detection unit of target nucleic acids.
 4. The biochemical treatment device according to claim 3 wherein said detection unit has cassettes with nucleic acid microarrays for detecting the target nucleic acids and said cassettes are arranged corresponding to the said lines of reaction area.
 5. The biochemical treatment device according to claim 1 wherein said nozzles are pipette chips which can be mounted and removed to said dispensing unit.
 6. The biochemical treatment device according to claim 5 wherein said dispensing unit is provided with a mechanism to mount and remove said pipette chips.
 7. The biochemical treatment device according to claim 1 wherein the biochemical treatment is a treatment using nucleic specimens.
 8. The biochemical treatment device according to claim 5 wherein a pipette chip accommodation unit accommodating said pipette chips can be mounted on said base stand.
 9. The biochemical treatment device according to claim 3 wherein a plurality of said base stands are provided corresponding to each of said units.
 10. The biochemical treatment device according to claim 1 wherein said reaction area comprise wells and a large number of wells are arranged on a plate in a lattice-like manner to form a plurality of said lines of reaction area.
 11. The biochemical treatment device according to claim 10 wherein said wells are covered with a protective sheet before a testing operation starts for preventing mixture of contaminants.
 12. The biochemical treatment device according to claim 11 wherein said dispensing unit is provided with an opening mechanism for opening said protective sheet. 